This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Specific Aims: 1. To determine if pre-clinical PS1 mutation carriers will perform significantly worse than their non-mutation carrying kin on neuropsychological tests measuring episodic memory and executive function as they approach the age of disease onset. 2. To determine if pre-clinical PS1 mutation carriers will have a higher prevalence of depression and higher levels of depressive symptoms than their non-mutation carrying kin despite being unaware of their genetic status. 3. To determine if biomarkers of AD pathogenesis such as CSF Ab oligomers will be found to be elevated in pre-clinical PS1 mutation carriers.